Microsoft is doubling down on its commitment to the tantalizing field of quantum computing, making a strong bet that it is possible to create a scalable quantum computer using what is called a topological qubit.

Longtime Microsoft executive Todd Holmdahl – who has a history of successfully bringing seemingly magical research projects to life as products – will lead the scientific and engineering effort to create scalable quantum hardware and software.

“I think we’re at an inflection point in which we are ready to go from research to engineering,” said Holmdahl, who is corporate vice president of Microsoft’s quantum program.

Holmdahl, who previously played a key role in the development of the Xbox, Kinect and HoloLens, noted that success is never guaranteed. But, he said, he thinks the company’s long investment in quantum research has been fruitful enough that there’s a clear roadmap to a scalable quantum computer.

“None of these things are a given,” Holmdahl said. “But you have to take some amount of risk in order to make a big impact in the world, and I think we’re at the point now that we have the opportunity to do that.”

Microsoft has hired two leaders in the field of quantum computing, Leo Kouwenhoven and Charles Marcus. The company also will soon bring on two other leaders in the field, Matthias Troyer and David Reilly.

Marcus is the Villum Kann Rasmussen Professor at the Niels Bohr Institute at the University of Copenhagen and director of the Danish National Research Foundation-sponsored Center for Quantum Devices.

Kouwenhoven is a distinguished professor at Delft University of Technology in the Netherlands and was founding director of QuTech, the Advanced Research Center on Quantum Technologies.

Marcus and Kouwenhoven have been collaborating with Microsoft’s quantum team for years, with Microsoft funding an increasing share of the topological qubit research in their labs. After they join Microsoft, they will retain their academic titles and affiliation to their host universities, continue to run their university research groups and contribute to building dedicated Microsoft quantum labs at their respective universities.

Both researchers say that joining Microsoft is the best path to ensuring that their breakthroughs can help create a scalable quantum computer.

“It’s very exciting,” Kouwenhoven said. “I started working on this as a student way back, and at that time we had not a clue that this could ever be used for anything practical.”

Kouwenhoven’s collaboration with Microsoft began casually enough, after a visit to the company’s Santa Barbara, California, lab and a “nice walk along the beach” with Michael Freedman, the lab’s director and a specialist in topological mathematics.

After years of scientific collaboration, Kouwenhoven said, they’ve reached a point where they can benefit from an engineer’s perspective on how to bring the work to reality.

“The engineering will also help move the science forward,” Kouwenhoven said.

That’s important because Microsoft isn’t just interested in creating one qubit that can work in one perfect lab environment – what Marcus calls “a demonstration of quantum information.”

Instead, the company hopes to create dependable tools that scientists without a quantum background can use to solve some of the world’s most difficult problems. By doing that, they believe they will help usher in a “quantum economy” that could revolutionize industries such as medicine and materials science.

Marcus – whose collaboration with Microsoft began almost by happenstance when he happened to be seated next to Microsoft’s Freedman at a dinner some years ago – said he came to realize that a quantum economy would never be realized unless the scientists and the engineers began partnering more closely.

“I knew that to get over the hump and get to the point where you started to be able to create machines that have never existed before, it was necessary to change the way we did business,” Marcus said. “We need scientists, engineers of all sorts, technicians, programmers, all working on the same team.”

That effort includes bringing other longtime collaborators on board.

Troyer is currently a professor of computational physics at ETH Zurich in Switzerland, one of the leading universities in the world. Among his areas of expertise are simulations of quantum materials, the testing of quantum devices, optimization of quantum algorithms and the development of software for quantum computers.

Reilly, an experimental physicist, is a professor and director of the Centre for Quantum Machines at the University of Sydney in Australia. He leads a team of physicists and engineers working on the challenges of scaling up quantum systems.

Making the building blocks of a quantum computer

Microsoft’s approach to building a quantum computer is based on a type of qubit – or unit of quantum information – called a topological qubit.

Qubits are the key building block to a quantum computer. Using qubits, researchers believe that quantum computers could very quickly process multiple solutions to a problem at the same time, rather than sequentially.

One of the biggest challenges to building a working quantum computer is how picky qubits can be. A quantum system can only remain in a quantum state when it’s not being disturbed, so quantum computers are built to be in incredibly cold, unique environments.

The Microsoft team believes that topological qubits are better able to withstand challenges such as heat or electrical noise, allowing them to remain in a quantum state longer. That, in turn, makes them much more practical and effective.

“A topological design is less impacted by changes in its environment,” Holmdahl said.

At the same time as Microsoft is working to build a quantum computer, it’s also creating the software that could run on it. The goal is to have a system that can begin to efficiently solve complex problems from day one.

“Similar to classical high-performance computing, we need not just hardware but also optimized software,” Troyer said.

To the team, that makes sense: The two systems can work together to solve certain problems, and the research from each can help the other side.

“A quantum computer is much more than the qubits,” Reilly said. “It includes all of the classical hardware systems, interfaces and connections to the outside world.”

An even smarter cloud, and the ability to solve seemingly intractable problems

With effective quantum hardware and software, quantum experts say they could create vast computing power that could address some of the world’s most pressing problems, from climate change and hunger to a multitude of medical challenges.

That’s partly because the computers could emulate physical systems, speeding up things like drug development or our understanding of plant life. Researchers say the intelligent cloud could be exponentially more powerful, similar to how cell phones evolved into smart phones.

“There is a real opportunity to apply these computers to things that I’ll call material sciences of physical systems,” Holmdahl said. “A lot of these problems are intractable on a classical computer, but on a quantum computer we believe that they are tractable in a reasonable period of time.”

Kouwenhoven said that applies to the field of quantum physics itself, such as research into dark matter and other fundamental questions about our understanding of the universe itself.

“I would find it interesting to go back to my science background and use the quantum computer to solve quantum problems,” he said.

The transistor and the ash sucker

Then there’s the vast unknown. Computer scientists will often point out that when scientists invented the very first transistor, they had no way of conceiving of an application like a smart phone.

“My guess is that back in the 40s and 50s, when they were thinking about the first transistor, they didn’t necessarily know how this thing was going to be used. And I think we’re a little bit like that,” Holmdahl said.

One of those inventors was Walter Brattain. He grew up in the same small town of Tonasket, Washington, as Holmdahl. Being a technology history buff, Holmdahl has long been fascinated by Brattain’s life.

With quantum computing, Holmdahl said he sees an opportunity to be among the people who are following in Brattain’s footsteps.

“The opportunity to be at the beginning of the next transistor is not lost on me,” Holmdahl said.

When he took this role, Holmdahl also was thinking about another man who’s had a great influence on his life: His 20-year-old son, who told Holmdahl that if you think you’re one of the smartest guys at the table, you need to find a new table.

“This is definitely a new table for me,” said Holmdahl, a Stanford-educated engineer who now spends his free time reading about things like quantum physics and entanglement.

When Marcus thinks about what a quantum computer could do, he often thinks about an old car his family once had. It was a top-of-the-line car of its day, with all the latest technologies — including a dashboard gadget designed to suck ash directly from a cigarette.

At the time, Marcus has often thought, someone must have believed that was as good as it was ever going to get in car technology.

“Nobody, when they were designing ash suckers, was thinking about self-driving cars,” he said.

The same thing could easily apply to computational power.

“People who think of computation as being completed are in the ash sucker phase,” he said.